btw it is possible to co-op with specific people in Demon’s Souls but it’s a bit of a bother to do so.

You’ll need to arrange with the person you intend to play with a specific spot where you’ll drop your blue stone, or where you’ll find his. Usually placing it in a more secluded, hidden part of the stage is best – that way you’ll avoid a random person taking your stone.

I’ve done this a few times and it’s pretty fun playing with your pals!